RESUMO As florestas amazônicas de bambu estão localizadas em uma importante região de alta biodiversidade no Brasil, Peru e Bolívia, formando a maior reserva florestal de bambu nativo do mundo. Contudo, os bambus dessas florestas possuem características que dificultam sua propagação. Objetivou-se avaliar a ação biocida de mistura preservativa para plantas no controle de contaminantes, durante o estabelecimento in vitro de Guadua latifolia (Bonpl.) Kunth, uma espécie nativa da região. Segmentos nodais foram cultivados em meio de cultura semissólido contendo mistura preservativa para plantas (PPMTM), nas concentrações de 0; 1; 2; e 3 mL L-1, e suplementado com 2 mg L-1 de 6-benzilaminopurina. As variáveis analizadas foram número de brotos, porcentagem de contaminação bacteriana e fúngica, e sobrevivência de brotos. Os tratamentos com o biocida sintético foram eficientes no controle da contaminação in vitro ocasionada por bactérias e fungos (Fusarium sp.), apresentando, também, a maior taxa de sobrevivência dos brotos regenerados. Para o estabelecimento in vitro dessa espécie nativa de bambu, recomenda-se o uso de 2 mL L-1 de PPMTM.

ABSTRACT The Amazonian bamboo forests are located in an important region of high biodiversity in Brazil, Peru and Bolivia, forming the largest native bamboo forest reserve in the world. However, the bamboos from these forests have characteristics that hinder their propagation. This study aimed to evaluate the biocide action of a plant preservative mixture for controling contaminants, during the in vitro establishment of Guadua latifolia (Bonpl.) Kunth, a species native to the region. Nodal segments were cultured in a semi-solid medium containing Plant Preservative Mixture (PPMTM), at the concentrations of 0; 1; 2; and 3 mL L-1, and supplemented with 2 mg L-1 of 6-benzylaminopurine. The analyzed variables were number of shoots, percentage of bacterial and fungal contamination, and shoot survival. The treatments with the synthetic biocide were efficient in controlling the in vitro contamination caused by bacteria and fungi (Fusarium sp.), also presenting the highest survival rate of regenerated shoots. For the in vitro establishment of this native bamboo species, the use of 2 mL L-1 of PPMTM is recommended.

Various factors affect spatial genetic structure in plant populations, including adult density and primary and secondary seed dispersal mechanisms. We evaluated pollen and seed dispersal distances and spatial genetic structure of Carapa guianensis Aublet. (Meliaceae) in occasionally inundated and terra firme forest environments that differed in tree densities and secondary seed dispersal agents. We used parentage analysis to obtain contemporary gene flow estimates and assessed the spatial genetic structure of adults and juveniles. Despite the higher density of adults (diameter at breast height ; 25 cm) and spatial aggregation in occasionally inundated forest, the average pollen dispersal distance was similar in both types of forest (195 ± 106min terra firme and 175 ± 87 m in occasionally inundated plots). Higher seed flow rates (36.7% of juveniles were from outside the plot) and distances (155 ± 84 m) were found in terra firme compared to the occasionally inundated plot (25.4% and 114 ± 69 m). There was a weak spatial genetic structure in juveniles and in terra firme adults. These results indicate that inundation may not have had a significant role in seed dispersal in the occasionally inundated plot, probably because of the higher levels of seedling mortality.

O objetivo deste trabalho foi avaliar a diversidade genética em duas populações de Carapa guianensis Aubl. (andiroba), no Estado do Acre, e comparar os parâmetros de diversidade com os observados em outras populações da espécie (no Brasil: Flona Tapajós, PA, Porto Acre, AC; e na Costa Rica). Foram avaliados 77 indivíduos adultos com sete locos polimórficos de microssatélites. Observaram-se 51 alelos nas duas populações, em que o número efetivo de alelos por loco (Âe = 3,2) foi inferior ao número médio de alelos por loco (Â = 7,3), o que indica elevado número de alelos com baixa freqüência. Os valores estimados de f não diferiram de zero, o que mostra que não ocorre endogamia nas populações. A taxa de cruzamento aparente foi alta (t a = 1,11 na população Porto Acre, e t a= 0,88 na de Rio Branco), resultado indicador de que a espécie se reproduz por alogamia. Foi observado, por meio das estimativas de Â, He (diversidade gênica) e Ne (número efetivo populacional) que as populações de andiroba, comparadas neste trabalho, tiveram padrões de diversidade semelhantes, porém, proporções de alelos raros diferentes.

The objective of this work was to evaluate the genetic diversity of two Carapa guianensis Aubl. (crabwood) populations, in the State of Acre, Brazil, and to compare the diversity estimations with those obtained in other populations of the species (in Brazil: Flona Tapajós, PA, Porto Acre, AC; and in Costa Rica). Seventy-seven individuals were assessed using seven polymorphic microsatellite loci. Fifty-one alleles were observed in the two populations, in which the effective number of alleles per locus (Âe = 3.2) was lower than the average number of alleles per locus (Â = 7.3), which indicates a high number of low frequency alleles. The estimated f values did not differ from zero, showing that inbreeding does not occur in these populations. The apparent outcrossing rate was high for both populations (t a = 1.11 in Porto Acre population, and t a = 0.88 in Rio Branco), indicating that this species reproduces by outcrossing. Comparing the estimates of Âe, He (gene diversity) and Ne (effective population number), it was observed that the general patterns of genetic diversity were similar. However, the number of rare alleles differ between populations.